Evaluation of Fatigue Damage in Short Carbon Fiber Reinforced Plastics Based on Thermoelastic Stress and Phase Analysis

Short carbon fiber composite materials are receiving a lot of attentions because of their excellent moldability and productivity, however they show complicated behaviors in fatigue fracture due to the random fibers orientation. In this study, thermoelastic stress analysis (TSA) using an infrared thermography was applied to the evaluation of fatigue damage in short carbon fiber composites. Second harmonic component of thermoelastic temperature change that is obtained by lock-in processing based on double-frequency against loading frequency was conducted to identify the turbulence in thermoelastic waveform due to fatigue damage evolution. It was found that the portions showing high second harmonic component values coincided with the portions where delamination damages were detected.